Anchal Singhal

Challenges with Mosquito-borne Viral Diseases: Outbreak of the Monsters

BACKGROUND The viruses responsible for mosquito-borne diseases are on an exploring mode, expanding their horizon, adapting to the situation and comfortably making their presence felt globally, from South Africa to Asia, Europe and United States. The current global scenario and recent documentations indicate towards the real monsters, outbreak of Zika, dengue and chikungunya viruses. Zika, dengue and chikungunya viruses are positive sense single-stranded RNA arbovirus and so their initial symptoms are almost 80% similar and all three are spread by mosquitos which bite during the day. Zika virus may damage brain by targeting the neuron cells in babies, and thereby it is very perilous to pregnant women. Dangerous Type: A less common but highly dangerous type of dengue is one which causes haemorrhagic fever and shock syndrome which are lethal. Chikungunya is not as lethal as Zika and dengue are, but it triggers joints pain which could last for months and even for years. CONCLUSION The vaccines against Zika, dengue and chikungunya viruses are at different stages of development. The challenges associated with the epidemic wave of Zika, dengue and chikungunya viruses have been explained and the current status of drug/ vaccine development against these viruses has been reviewed.

Functional Calixphyrins: Synthetic Strategies and Applications

Calixphyrins are hybrid macrocycles that contain both sp2- and sp3-hybridized carbon atoms and hence bear analogy to both porphyrins and calixpyrroles. Due to the presence of sp3-hybridized carbon atoms, π-conjugation is disrupted in calixphyrins, which leads to conformational flexibility. Hence, these molecules find a use in anion binding, host-guest chemistry and metal-coordination chemistry. During the last decade, studies on calixphyrins have been a topic of wide interest to researchers. Various functionalities have been introduced to the structure of calixphyrins, leading to the development of expanded calixphyrins, core-modified calixphyrins and N-confused calixphyrins with diverse applications. This review outlines the detailed historical origin of the synthesis of calixphyrins with emphasis on current research and development in this area. The modular syntheses of normal calixphyrins, expanded calixphyrins, core-modified calixphyrins and N-confused calixphyrins are also discussed, along with their applicative aspects.

Free Radical Copolymerization of Acrylamide and N-Vinylpyrrolidone Catalyzed by Iron(III)porphyrins in the Presence of Ionic Liquids

Polymers are important for many technological applications. The high demand for new materials requires the preparation of polymers with enhanced properties, and the copolymerization technique has been widely used to achieve this target. Copolymerization greatly increases the variety of polymer products with specifically designed properties by changes in the nature and relative amounts of monomer units in the copolymer product. Acrylamide and vinylpyrrolidone have been among the most widely used monomers and their homoand copolymers frequently appear in applications ranging from mining to clinical medicine and electrochemical devices. Depending on the arrangement of twomonomers in the copolymer chain, copolymers can be categorized as random, alternating, block and graft copolymers. Horseradish peroxidase (HRP) is known to produce novel polyaromatics through oxidative polymerization using water, water-miscible organic solvents, micellar systems, reversed micellar systems, biphasic systems and Langmuir trough systems. The first catalytic activity of HRP was observed by Louis Antoine Planche when “gaiac” resin was found turning blue in the presence of HRP. It was probably the HRP-catalyzed oxidation reaction of 2,5-di-(4-hydroxy-3-methoxyphenyl)3,4-dimethylfuran, a minor constituent of “gaiac” resin and formerly known as guaiaconic acid. Further studies revealed the structure and catalytic reactions of HRP in aqueous and organic media. Peroxidase-catalyzed vinyl polymerizations have been demonstrated in recent years with significant control of polymer molecular weight and yield depending on the reaction conditions. But these enzymes are very expensive, in addition to their low stability. On the other hand, 5,10,15,20¡tetraarylporphyrinatoiron(III) chlorides provide promising and less compromised applications. These metalloporphyrins react with oxygen donors such as hydrogen peroxide or alkyl peroxide, to mimic the reactions of cytochrome P450, peroxidase and others under mild conditions, as previously shown by our group. The reactions of metalloporphyrins with hydrogen peroxide have attractedmuch attention as hydrogen peroxide is a biologically important and environmentally clean oxidant. In recent years, ionic liquids (ILs) have emerged as green solvents and are getting an upsurge of interest for

Synthesis of Selenium and Tellurium Core-Modified Azuliporphyrinogens and Benziporphyrinogens and Corresponding Carbaporphyrinoids

The synthesis of selenium and tellurium core-modified carbaporphyrinogens was carried out by the reaction of functional selenophene/tellurophene diols with azulene or a benzitripyrrane in the presence of acid. The products were obtained in moderate yields and were characterized by using 1H and 13C NMR, UV-vis, FT-IR, CV, and HRMS spectroscopic techniques. Further, oxidation of the obtained core-modified carbaporphyrinogens in the presence of DDQ in CHCl3 afforded the corresponding carbaporphyrins in good yields. Benziporphyrins showed no indication of a ring current or macrocyclic aromaticity as confirmed by using proton NMR spectroscopy, but the addition of TFA gave rise to the formation of weakly diatropic dications.